The overall objective of the proposed research is to determine the mechanisms by which ovarian hormones regulate amounts and activities of specific uterine enzymes. More specifically, we plan to determine the mechanisms by which progesterone and estradiol control rates of enzyme synthesis and degradation in the endometrium and myometrium of the pseudopregnant rat uterus during decidualization. During the cellular differentiation of decidualization, deciduoma cell types will be biochemically characterized and the hormonal control of their rates of enzyme synthesis and division determined. Further experiments will examine potential mechanisms of protein degradation in the uterus, including degradation by lysosomal cathepsin D. An understanding of mechanisms of control of protein synthesis and degradation in the endometrium and myometrium of the uterus should contribute to our understandingof the processes of implantation and early placental development.